Today I tried to update our pbx to v15. Made a backup of V14, removed it, removed IIS, applied all win updates, installed V15 using backup-config, logged in to console. Run thru the "config wizzard", which at last step won't except my (end-user-)license. An error message with "internal server error 500" followed by "license activation failed - license_error" occured. All license infos were read from backup and looks right. What can I do to get V15 running?